COPPER PROCESSING

use of smelting or leaching, usually followed by electrolytic refining or recovery, to turn the ore into a form from which products can be fashioned. Included in this article also is a discussion of the mining of copper and of its preparation for processing. In its pure form or as an alloy, copper (Cu) is one of the most important metals in society. The pure metal has a face-centred cubic crystal structure, and there is no critical temperature at which this crystal structure changes. Consequently, it is ductile and possesses a high level of electrical and thermal conductivity, making it attractive for a wide range of ornamental and practical applications. With cold-working, copper becomes harder, but it can be made soft again with the heat treating process known as annealing. Additional reading Comprehensive and up-to-date information on many aspects of metallurgy, individual metals, and alloys can be found in convenient reference-form arrangement in the following works: Metals Handbook, 9th ed., 17 vol. (197889), a massive and detailed source prepared under the direction of the American Society for Metals, with a 10th edition that began publication in 1990; Herman F. Mark et al. (eds.), Encyclopedia of Chemical Technology, 3rd ed., 31 vol. (197884), formerly known as Kirk-Othmer Encyclopedia of Chemical Technology, with a 4th edition begun in 1991; and its European counterpart, the first English-language edition of a monumental German work, Ullmann's Encyclopedia of Industrial Chemistry, 5th, completely rev. ed., edited by Wolfgang Gerhartz et al. (1985 ). The Editors of the Encyclopdia BritannicaAnil K. Biswas and W.G. Davenport, Extractive Metallurgy of Copper, 2nd ed. (1980), is a comprehensive text detailing the mineral processing as well as the hydrometallurgical and pyrometallurgical processes commonly used for the extraction of copper from ores; it includes operating data on selected plants around the world. Joseph R. Boldt, Jr., The Winning of Nickel: Its Geology, Mining, and Extractive Metallurgy (1967), covers geology, mining, mineral processing, and extractive metallurgy of nickel and associated metals such as copper and cobalt. John Campbell Taylor